Miraheze is a "wiki farm", (the Wikimedia support wiki uses such a term to mean "a 'farm' that grows wikis", which isn't much clearer. They are a large-scale wikihost.) They are a free, ad-free wiki host, funded through donation, and they currently host 8,800 wikis. They run the latest version of Mediawiki which is the same software Wikipedia uses, and as a result their wikis look and feel just like Wikipedia. The farm is operated by a non-profit and you keep the rights to all your own work.
Features
On the main page of their support wiki, they list the following features:
- It's free, and there are no ads.
- You can add over 300 extensions, and there are dozens of "skins" for your wiki.
- Running the latest version of Mediawiki
- Volunteer customer support
- Open-source code.
- Custom domains are possible.
- All wikis have HTTPS, and have CSS templates.
- Free image repository.
The things I don't like
I adore my wiki, but there are several things I dislike. Firstly, it doesn't have ALL mediawiki extensions. There is an extension that allows me to replace all instances of something across an entire wiki (like find and replace, but wiki-wide), which just isn't available with Miraheze, which is a shame because several times now I've had to go to a bunch of pages across my wiki to replace instances of something if I move or rename a page.
Also, I am unable to add a picture icon to the upper-left. So for example, on Wikipedia, in the upper-left it shows a puzzle-piece globe next to the word "Wikipedia". I can't do that. Also, I can't change the wiki's favicon.
Impressions
I have my own wiki for my writing project, and I really like it. I had the option to set my wiki to "private" (which I did), and it does all the setup work for me, and all the permissions and whatnot. It requires hardly any technical know-how, and I didn't have to bother with setup, I was able to just start creating pages and filling out the wiki. I will say though that I am a little concerned about losing my work, if it's on someone else's server, but their support wiki says that they have multiple backup servers, so I feel safe enough to use it.